ANS-C01 Network Design Practice Question
A company is designing a network for a multi-tier application. The web tier must be accessible from the internet, and the application tier must only be accessible from the web tier. Which architecture should they use?
⚠ Common exam trap
The ANS-C01 exam often tests the misconception that a NAT Gateway can provide inbound internet access to private instances, but it only enables outbound traffic; the trap here is confusing NAT Gateway with Internet Gateway for inbound connectivity.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Web servers in public subnets with an Internet Gateway, and application servers in private subnets with security groups allowing traffic only from the web tier
It places the web servers in public subnets with an Internet Gateway (IGW) to allow direct inbound traffic from the internet, while the application servers reside in private subnets with security groups that explicitly permit traffic only from the web tier's security group. This ensures the application tier is not directly reachable from the internet, adhering to the principle of least privilege and defense in depth.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Web servers in private subnets with a NAT Gateway for outbound traffic, and application servers in public subnets
Why it's wrong here
Web servers need to be accessible from the internet, so they should be in public subnets.
- ✓
Web servers in public subnets with an Internet Gateway, and application servers in private subnets with security groups allowing traffic only from the web tier
Why this is correct
This follows best practices for multi-tier architectures.
- ✗
All servers in a single VPC with VPC Peering to another VPC
Why it's wrong here
VPC Peering is not relevant to tier isolation.
- ✗
Web servers and application servers in public subnets, each with their own security group
Why it's wrong here
Placing application servers in public subnets unnecessarily exposes them to the internet.
Visual reference
Go deeper
Related to this question
About these practice questions
One of 1,621 original ANS-C01 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the ANS-C01 exam.